摘要:

AbstractThe bond stretching vibrations of XF5molecules withD3hsymmetry are treated computationally on the Morse oscillator model in which the bond oscillators are coupled harmonically. Each calculation involves four parameters for two types of Morse potential and three parameters for the kinetic‐energy, potential coupling terms. The eigenvalue formula for overtone and combination states up to three are presented and can be used to predict all the vibrational energy levels from local mode molecules through normal mode molecules. For PF5, AsF5and VF5, the coupled Morse oscillator model gives a prediction in good agreement with the experimental dat

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090401

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractThe quenching processes of the excited singlet state of pyrene by triphenylamine, diphenylamine andN,N‐dibenzylaniline in various solvents at room and lower temperature have been studied with both static state fluorescence spectroscopy and fluorescence lifetime techniques. On the basis of experimental data, a preliminary quenching mechanism has been discussed. The geometrical configuration models of the exciplexes formed between the excited pyrene and aromatic amines in nonpolar solvents were propose

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090402

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractThe title compound has been synthesized and its crystal structure was determined by X‐ray crystallographic method. The crystal is triclinic, space groupP‐1, with unit cell dimensionsa= 6.146 (5),b= 8.473(6),c= 14.383(5) Å; α = 77.47 (4), β = 82.84 (4), γ = 69.00 (8)° andZ= 2. The results obtained reveal that the molecule of the title compound keeps a long conjugative system involving CC double bond, cyclopropane ring, carbonyl group and isoxazolinone ring and adopts a low energy conformation including s‐transof CC double bond, s‐cisof carbonyl group with respect to the three‐membered ring and like‐s‐transof carbonyl group with the carbonyl group within t

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090403

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractA method to derive the atomic multipole moments cumulatively up to quadrupole moments was developed. The multipole moments are obtained by least‐square simulating the molecular electrostatic potentials. Only the components of the term of highest order in the atomic multipole expansion are optimized while the lower terms remain fixed. The calculations on HF, H2O and NH3show that the cumulative method can give reasonable qualitative and fairly good quantitative result

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090404

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractAn equation to express ion exchange selectivity coefficient was derived and used for calculating that of PPY film with the results obtained by cyclic voltammetric measurement. PPY film was synthesized by electrochemical method in aqueous solution using K4Fe(CN)6as supporting electrolyte, and the anions were doped into the film. Ion exchange behaviour of doped Fe (CN)63‐/4‐in the PPY film with Cl−, NO3−or F−ions in solution has been studied, and the corresponding ion exchange selectivity coefficients were d

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090405

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractCrosslinking experiments for the chiral stationary phase OV‐225‐L‐Val‐t‐butylamide within both fused silica and glass capillary columns have been carried out. Amino acid enantiomers were separated on crosslinked columns by both GC and SFC methods. In SFC, theavalues of amino acid enantiomers are independent of the density of the mobile phase, and they are hig her than those obtained by GC for the tested enantiomers with the same column due to the lower column temperature us

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090406

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractTwenty‐six derivatives of tris[(phenyldimethylsilyl)methylene]tin carboxylates have been prepared. All compounds are new and characterized through elemental analysis IR spectra, and1H,13C,110Sn NMR spectral studies. The spectral results showed that all compounds are four coordinated organotin compounds. The Δv(=υ OOasymp−υ COsymp) of them are over 300 cm−1. The chemical shifts (δ) of119Sn of ArCO2Sn(CH2SiMe2Ph)3and ArOCH2CO2Sn(CH2SiMe2Ph)3give good straight‐line correlation withpara‐substituent constants. These compounds have good acaricide activity, but their action on the mite are slowe

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090407

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractThe electronic structures of 17 perchlorofiuoroolefins and perfluoroolefins were calculated using the MNDO method. Based on these calculations combined with the perturbation theory, a good structure‐reactivity relationship of perchlorofluoroolefins has been established. In the case of internal olefins, the direction of nucleophilic attack is governed not only by the perturbation energy of the ground state, but also by the stability of the anionic intermediate and the activation energy of the reactio

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090408

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractThe reactions of 1,3‐dinitro‐2‐chloro‐5‐trifluorotoluene (DNCTT)(1)and its bridged compounds with bidentate nucleophiles have been investigated. Primary or secondary diamines and diethylene glycol react with1and its bridged derivatives by replacing the substituent groupparato CF3, whereas ethanedithiol reacts either by replacing the substituent groupparato CF3or by displacing both groups and a nitro group. The results have been rationalized in terms of electronic effects and nucleophilicity of the nuc

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090409

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractSodium dithionite‐initiated addition of RFI (1) [RF=1a, Cl(CF2)4; 1b, Cl(CF2)6; 1c, Cl(CF2)6; 1d,n‐C6F13; 1e,n‐C3F17] to the properly protected glucose derivatives 2, 9, 12 and 15 gave polyfluoroalkylated glucose derivatives 7, 11, 14 and 17 respectively in good yields after reduction and deprotection. These compounds are strongly surface a

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090410

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY